Adding a A/C unit

[gmartin2]

Thanks Russel;

The home is a ~1957 vintage. Owner speculated that it might be the original unit. At any rate it is probably past its normal lifespan. He is considering a new unit of higher efficiency.

Once again thankyou.
Geo

[JLilly]

Like said earlier an A/C unit can be installed on almost anything forced air provided you have room for the evaporator coil and the blower can provide the 400 cfm per ton necessary.

[quote=dandersen]As Russell indicated there is no way to size an air conditioner in accordance with the square footage of the house. Some contractors can do this based on information which is common knowledge to them such as common type construction for your particular geographical area etc. but there are too many factors involved for you as a home inspector to make that determination.
That's all informative information, but to the layman, a little confusing. I'm not asking for an explanation, or some clearification, but sometimes, a simple answer to give the clients, will make more sense than trying to explain it all.

[David A. Andersen]

I explain it so you will understand it and give a correct "simple answer"

[Russel Ray]

Originally Posted by JLilly

Like said earlier an A/C unit can be installed on almost anything forced air provided you have room for the evaporator coil and the blower can provide the 400 cfm per ton necessary.

Is 400 cfm the minimum that units come with nowadays? Or how did you choose that number?

[JLilly]

400 cfm is the standard. There may be some exotic units that require a different value but 400 is the norm. http://www.acca.org/tech/manualj/ I've been a HVAC tech for 20 years. Manual J is the means by which a house is properly sized. It takes into consideration insulation values, sq ft, how many windows etc. Many are not sized by that method but to do it correctly that is the standard.